More about Mary I at this site:
MARY IN HENRY VIII'S REIGN
Mary Tudor was the only child born to Henry VIII and Catherine of Aragon to survive childhood. Had she been born a boy, it is likely that the whole of English history would have been different (but probably less interesting!).
Mary had a good childhood as a young princess, and was the center of court attention in her earliest years. But, as the years progressed and no little brothers followed, Mary's father began to look into the alternatives. Eventually, Henry sought an annulment from Catherine, and married his second Queen: Anne Boleyn. Mary was declared illegitimate and was to no longer be called "princess", but rather "The Lady Mary".
When Anne Boleyn gave birth to Elizabeth, Mary was sent to attend the new young Princess in her household. Soon Elizabeth would be declared a bastard as well, since her mother also failed to produce a male heir for Henry.
Shortly after the death of Anne Boleyn, Henry wed Jane Seymour, who sought to reconcile the King with his two daughters. Henry and Jane visited Mary and after, she wrote letters to the Holy Roman Emperor Charles V (her cousin) and the Pope stating that her parent's marriage had not been valid. [Mary was able to get an additional message to them, in secret, saying that she wrote the letters under duress.] After that, she returned to court, although her title of Princess still had not been restored.
In October 1537, Queen Jane gave birth to Edward, Henry's longed for son and Mary stood as the young Prince's godmother at the christening. The court was soon plunged into mourning as Jane died two weeks after Edward's birth.
In January 1540, Mary gained yet another stepmother: Anne of Cleves. Although they shared different religions (Mary was Catholic, Anne a Lutheran), the two women became fast friends and would remain so until Anne's death in 1557. Unfortunately Anne's marriage to Henry wasn't so long-lived and she was divorced in July of the same year.
Shortly after the annulment of his marriage to Anne of Cleves,Henry took another wife [now his 5th], Kathryn Howard. Kathryn was probably 18 years old, making Mary six years older than her new stepmother. Mary was apparently appalled at her father's action and there were come quarrels between Mary and Kathryn during the young Queen's reign. That reign turned out to be all too short, as she was arrested, tried and executed for adultery in 1542.
At this time of emotional upheaval, Mary fell seriously ill and may have been in danger of losing her life. Her father was concerned enough to send his own doctors to look after her.
Henry's last Queen was Katherine Parr, who was about four years older than Mary. They were married in 1543, and she survived Henry at his death in 1547. All three of Henry's children attended the wedding at Hampton Court. Mary was friends with her last stepmother, although they too had religious differences, as Katherine was a strong supporter of the Reformed Church.
When Henry VIII began to fall ill, he drafted his will declaring that Edward would be his heir and Mary was to follow him if the young Prince were to die childless. Elizabeth was also included, and she would take the throne if Mary were to die without an heir. As we know in hindsight, this is exactly what was to happen.
MARY IN EDWARD VI'S REIGN
Henry VIII died January 28, 1547, leaving his 9 year-old son as King. The young Edward was a supporter of the Protestant faith, although Mary seems to have hoped at one point he would see the error of his ways and return England to the Church of Rome.
Alas, this was not to be. She defied Edward's Act of Uniformity and openly celebrated Mass, which had been abolished. Edward and Mary struggled with this issue through the rest of the King's short reign.
Some time in 1552, Edward began to show signs of the illness that would eventually claim his life. He was reported to have a hacking cough that eventually resulted in him spitting up blood and tissue. Medical historians generally agree that he had tuberculosis.
Fearing Mary would return the country to the Catholic faith, powerful men in the realm, such as John Dudley, Duke of Northumberland and Henry Grey, Duke of Suffolk began to make their plans. Although they made moves to court Mary's favor, they worked secretly with their own agenda. Northumberland married his son Guildford to Suffolk's daughter Jane Grey, who would be in line for the throne after Mary and Elizabeth. By placing Jane on the throne in Edward's wake, they thought they would have a puppet they could control [although Jane seems to have had other ideas about that!].
Northumberland put his plans into action and convinced Edward to leave his crown to his cousin Jane.
MARY AND 'THE NINE DAYS QUEEN'
Mary realized that a plot was being hatched to place Jane on the throne. She had been urged by some friends to flee the country since they feared her life would be in danger. Mary knew that if she fled, she would forfeit all chances of becoming Queen and returning England to Catholicism, so she chose to remain and make a stand for her crown.
Edward died on July 6, 1553. Shortly afterwards, Northumberland informed Jane at Syon house that Edward had left the crown to her and that she was now Queen of England. Mary, meanwhile, was in East Anglia. Northumberland and three of his sons went to take Mary into custody. Mary was at this time moving around with a growing army of supporters. She knew that he must have confirmation of her brother's death, because it would be treason to declare herself Queen otherwise. She received news from a reliable source that Edward was indeed dead, and promptly sent proclamations throughout the country announcing her accession to the throne.
Mary went to Framlingham Castle in Suffolk, which was better fortified. Her number of supporters was increasing and Mary took time to inspect her troops personally. The people of Suffolk were flocking to Mary and many of the leaders who were supposed to take her into custody instead went and begged for her pardon.
By this time, the Privy Council in London realized their error in going along with Northumberland's plot and declared Mary the true Queen of England. She left Framlingham for London on July 24.